General Anesthetics

Question 1

What does a complete anesthetic produce?

Answer 1

Unconsciousness
Unresponsiveness
Amnesia
Immobility
Autonomic stability to the anesthetic state

Question 2

Why isn’t Diethyl Ether used as a general anesthetic?

Answer 2

It is highly flammable

Question 3

How do modern general anesthetics achieve the best qualities?

Answer 3

They’re given as a combination to get the advantages of all the drugs

Question 4

What are the aspects of Ideal Surgical Anesthetics

Answer 4

Smooth and rapid induction
Produce unconsciousness
Produce amnesia
Maintain essential physiological functions, while blocking undesired reflexes
Skeletal muscle relaxation, but not respiratory muscles
Smooth, rapid, and uneventful recovery with no lasting adverse effects

Question 5

What types of drugs would be in a anesthetic cocktail?

Answer 5

Antimuscarinics
Various analgesics
Nitrous oxide and/or opioids
Antinicotinics
Antiemetics
Additional drugs

Question 6

What role do antimuscarinics play in anesthetic cocktails?

Answer 6

Minimize salivation, larygospasms, and reflex bradycardia

Question 7

What role do analgesics play in anesthetic cocktails?

Answer 7

Proprioceptive pain relief
Sedation
Amnesia

Question 8

What role do Nitrous oxide and opioids play in anesthetic cocktails?

Answer 8

Reduce anesthetic requirement, provide analgesia

Question 9

What role do antinicotinixs play in anesthetic cocktails?

Answer 9

Paralyze skeletal muscle

Question 10

What role do “additional drugs” play in anesthetic cocktails?

Answer 10

Maintain organ stability

Question 11

Why are general anesthetics not typically used in dental treatment?

Answer 11

Dental procedures are not usually as traumatic, so its not necessary or desirable to render the patient unconscious

Question 12

Membrane Lipid Based Theory

Answer 12

The direct action of anesthetics on proteins lead to alterations
aka: Anesthetics interact with hydrophobic sites on proteins and affect their function

Question 13

What sort of proteins are the likely targets of general anesthetics?

Answer 13

GABA receptors
Ligand activated ion receptors
CNS proteins

They interfere with the function of many proteins of neurochemical interest, but there is not a single target

Question 14

T/F - Anesthetics have been observed to have both pre and postsynaptic effects

Answer 14

True

Question 15

What is the reticular formation important for?

Answer 15

Major center supporting consciousness and alertness

Question 16

Anesthetics that effect the reticular formation do what?

Answer 16

By depressing the RF, they induce unconsciousness

Question 17

Anesthetics that effect the thalamocortical loop does what?

Answer 17

Induce unconsciousness

Question 18

What is the limbic system involved in?

Answer 18

Memory

Question 19

Inhibition of the limbic system would induce what?

Answer 19

Anesthetic-induced amnesia

Question 20

Anesthetics that affect the spinal cord will do what?

Answer 20

Disrupt pain pathways

Question 21

T/F - Anesthetics only need to depress one brain pathway to achieve anesthesia?

Answer 21

False - they need to depress many brain pathways

Question 22

What are the stages of general anesthesia?

Answer 22

1) Analgesia (induction)
2) Excitement
3) Surgical anesthesia
4) Medullary paralysis

Question 23

T/F - Modern anesthetic try to skip the steps of general anesthesia by being given in a cocktail

Answer 23

True

Question 24

What is the pathway of distribution of volatile anesthetics?

Answer 24

Alveoli –> Blood –> Briain

Question 25

What is the pathway of recovery of volatile anesthetics?

Answer 25

Brain --> Blood --> Alveoli

Question 26

What does a low blood:gas coefficient mean?

Answer 26

Anesthesia has low solubility (prefers the gas stage) Faster induction and recovery Ex: nitrous oxide

Question 27

What does a high blood:gas coefficient mean?

Answer 27

Anesthesia has a high solubility Slower induction and recovery exL Halothane

Question 28

What determines MAC %?

Answer 28

Olive oil solubility

Question 29

Drugs with a low MAC% have what?

Answer 29

High potency

Question 30

What are desirable properties for inhalation anesthetics?

Answer 30

Low MAC | Low blood:gas coefficient

Question 31

What are generalized pharmacological effects of volatile anesthetics?

Answer 31

Decrease the activity of cardiovascular system, respiration, kidney, skeletal muscle, and liver

Question 32

Nitrous oxide

Answer 32

Volatile Anesthetic with low blood:gas coefficient, and high MAC Used at concentrations of 20-50% (mostly as an anti-anxiety) Used in conjunciton with other more potent anesthetics so the other drugs can achieve more rapid onset and recovery

Question 33

Isoflurane

Answer 33

Improvement of halothane (less toxic, but less potent - lower B:G coefficient) MAC = 1.15% B:G = 1.4 Smells bad, so we want to knock the patient out with something else first

Question 34

Desflurane

Answer 34

MAC = 6% B:G = 0.45 Contraindicated in patients susceptible to malignant hyperthermia

Question 35

Seroflurane

Answer 35

MAC = 2% B:G = 0.65 More rapid acting that isoflurane

Question 36

Barbituates

Answer 36

IV anesthetics that act as CNS depressants by potentiating the activity of GABA receptors

Question 37

How do GABA receptors work?

Answer 37

When activated, release Cl in the cytoplasm to cause hyperpolarization, thus providing inhibitory influence on synaptic transmission

Question 38

How are Barbituates classified?

Answer 38

Based on the duration of action

Question 39

Classification of Barbituates

Answer 39

``` Ultra-short acting (15-30 min) Short acting (2-4 hrs) Intermediate acting (4-6 hrs) Long acting (6-8 hrs) ```

Question 40

What are the advantages of IV agents in anesthesia?

Answer 40

Rapid distribution (from vein to brain in seconds) Reduced cardiac depression No risk of malignant hyothermia Eliminate the risk of occupational exposure (only patient gets it)

Question 41

What is the major adverse effect of IV anesthetics?

Answer 41

Respiratory depression

Question 42

Thiopental

Answer 42

``` Ultra short acting barbituate Causes unconsciousness in 0.5-1 min 60% of dose reaches brain in 1 minute Consciousness returns in 5-10 minutes Largely has been replaced by Propofol ```

Question 43

Methoxhexital

Answer 43

Similar to thiopental, but 2.5x more potent, faster acting, and a shorter duration Sleep time is 5-7 minutes Cleared 3x faster than thiopental Faster recovery, and more favorable for dentistry

Question 44

Propofol

Answer 44

Most popular barbituate Rapid recovery and clearing General state is normal after clearing

Question 45

What is the induction dose for Propofol?

Answer 45

2-2.5 mg/kg

Question 46

What is the maintenance dose for Propofol?

Answer 46

50 ug/kg/min - 200 ug/kg/min

Question 47

Ketamine

Answer 47

Produces dissociation anesthesia Analgesia and amnesia with minimal effect on respiratory function Patient can blink and swallow, but doesn't process info (PCP-like drug)